trouble

If direct installation from CRAN doesn’t work, your R version might be too old. In that case, an update is really recommendable: r-project.org. If you can’t update R, try installing from source (github) via instGit or devtools as mentioned above. If that’s not possible either, here’s a manual workaround: click on Clone or Download - Download ZIP (top right, link), unzip the file to some place, then

This creates all R functions as objects in your globalenv workspace (and overwrites existing objects of the same name!).

license

This package is under the GPL license. I am fine with you doing whatever you want with it, provided that my name and credit remains attached to it. If you legally need a more permissive license, let me know and I can probably change it.